hysteresis

[nut]

hi
i'm nut .I have the question about hysteresis in abaqus cae.I try to got the parameter m,c,c1 and other from experiment for solve in strain rate by using your paper to solve but i don't know when we input parameter in abaqus cae in *hysteresis how it calculate together with neo hook energy function and output reaction force.I try many time to read your paper and abaqus manual but it not clear.

Thank you for your answer

Nut

[Jorgen]

Hello Nut,

I am not quite sure I understand your question. Have you been able to determine the material parameters from experimental data? If so, all you need to do is to make sure that the material parameters are appropriately converted to the format that is used by ABAQUS.

To use the hysteresis model, you first specify the properties of the hyperelastic material. Then you specify the hysteresis parameters using *Hysteresis.

- Jorgen

[nut]

Hi
I'm sorry for not clear question.Again I can calculate parameter A,C,m from experiment data right? and what about the rest of parameter. I mean lamda b and sigma B.How I calculate it? or How does abaqus calculate it? I would like to see step of calculation and then after we calculate the effective creep strain rate in network B already.I want to know how the effective creep strain rate relate with curve between Reaction force and displacement.I mean how to calculate it (My boundary condition is I make the rubber cylindical block and set displacement compress to somepoint and next step is set displacement return to original point.)

[Jorgen]

All you need to do is determine the necessary material parameters, the rest of the calculations, like the calculation of sigma B, are all taken care of by ABAQUS. If you are interested in the internal details of the calculation then you need to implement the model yourself.

I have developed my own UMAT routine for the BB-model that could be modified to output the creep strain rate in network B, see the UMAT (http://www.polymerfem.com/modules.php?name=User_Subroutines) section.

- Jorgen

[nut]

hello
I'm nut.I have to disturb u again for my question.So I read your thesis time-depentdent 260 page.I don't understand on what the different between high strain rate and slow strain rate.I saw only high strain rate curve higher than slow rate in the same true strain.Which parameter that different between high rate and slow strain rate.Because in your thesis told that the same rubber have the same parameter.I feel so confuse now.Any way in abaqus hysteresis as well,I don't know if i want to predict high strain rate which the parameter that different from slow rate.

Thank you very much
Nut

[Jorgen]

I might have misunderstood your question, but the point of the model is that you use the same material parameters independent of the applied strain rate.

That way you can determine the material parameters once for all, and then simulate any applied deformation history that you are interested in.

- Jorgen

[nut]

hi jorgen
Again,How I can change the strain rate in abaqus?.I have to use implicit right?

Thank you
Nut